1. Field of the Invention
The present invention relates to a pedometer for measuring the number of steps by detecting walking of a human body, particularly relates to a pedometer having a step number measuring function in walking and in running.
2. Description of the Related Art
In a background art, various pedometers capable of measuring the number of steps in walking and in running have been developed.
For example, according to a pedometer described in JP-UM-A-2-612 (column of scope of claims, FIG. 4), one sensor is mounted in a direction in which a sensitivity axis of the sensor is orthogonal to a length direction of the arm (12 o'clock-6 o'clock direction of timepiece), as a direction of detecting a physical motion, arm swinging is detected in walking and detecting a physical motion produced in an up and down direction of the body by an impact of landing in running to thereby enable to measure the number of steps in walking and in running.
However, although according to the pedometer, only the one sensor is used, a rear stage of the sensor needs to be prepared with two filters of a filter with an object of passing about 45 steps/minute to 60 steps/minute in walking (a normally assumed walk pitch is 90 steps/minute to 120 steps/minute, one swing is constituted by two steps when arm swinging is used for detection, and therefore, an output from the sensor is constituted by 45 steps/minute through 60 steps/minute of a value of a half of the 90 steps/minute through 120 steps/minute), and a filter with an object of passing 170 steps/minute through 190 steps/minute in running (a normally assumed running pitch in running is 170 steps/minute through 190 steps/minute and when landing is used for detection, the output from the sensor is constituted by the same 170 steps/minute through 190 steps/minute), and it is necessary to switch the filters in accordance with either of cases of detecting walking and running. Therefore, a problem of enlarging a circuit scale is posed.
Further, both in walking and running, one sensor output signal is counted as two steps, and therefore, regardless of the fact that one sensor output and one step correspond to each other in running, one sensor output signal is abandoned, a successive or preceding sensor output signal is counted as two steps, and therefore, depending on setting a mask time period, there poses a problem of bringing about a measurement error.
On the other hand, according to the invention described in JP-A-2004-290658 (paragraphs [0015] through [0020], FIG. 1 through FIG. 10), detection of the number of steps in walking and in running is realized by providing two sensors having sensitivity axes different from each other and a frequency analyzing portion.
However, according to the method, not only the two sensors are needed but also the frequency analyzing portion needs to be provided and there poses a problem that the circuit scale is enlarged.
It is a problem of the invention to provide a pedometer capable of measuring the number of steps in walking and in running by using one sensor and by a small circuit scale.